Department of Mechanical and Aerospace Engineering, PO Box 6106, West Virginia University , Morgantown, West Virginia 26506, United States.
Environ Sci Technol. 2017 Jan 17;51(2):968-976. doi: 10.1021/acs.est.5b06059. Epub 2016 Dec 30.
Pump-to-wheels (PTW) methane emissions from the heavy-duty (HD) transportation sector, which have climate change implications, are poorly documented. In this study, methane emissions from HD natural gas fueled vehicles and the compressed natural gas (CNG) and liquefied natural gas (LNG) fueling stations that serve them were characterized. A novel measurement system was developed to quantify methane leaks and losses. Engine related emissions were characterized from twenty-two natural gas fueled transit buses, refuse trucks, and over-the-road (OTR) tractors. Losses from six LNG and eight CNG stations were characterized during compression, fuel delivery, storage, and from leaks. Cryogenic boil-off pressure rise and pressure control venting from LNG storage tanks were characterized using theoretical and empirical modeling. Field and laboratory observations of LNG storage tanks were used for model development and evaluation. PTW emissions were combined with a specific scenario to view emissions as a percent of throughput. Vehicle tailpipe and crankcase emissions were the highest sources of methane. Data from this research are being applied by the authors to develop models to forecast methane emissions from the future HD transportation sector.
从对气候变化有影响的重型（HD）运输部门的泵到轮（PTW）甲烷排放情况记录不佳。在这项研究中，对为其提供服务的 HD 天然气燃料车辆以及压缩天然气（CNG）和液化天然气（LNG）燃料站的甲烷排放情况进行了描述。开发了一种新的测量系统来量化甲烷泄漏和损失。对二十二辆天然气燃料的过境巴士、垃圾车和长途（OTR）拖拉机的发动机相关排放进行了特征描述。在压缩、燃料输送、储存以及从泄漏中对六个 LNG 和八个 CNG 站的损失进行了描述。使用理论和经验模型对 LNG 储罐的低温沸腾压力上升和压力控制通风进行了描述。使用 LNG 储罐的现场和实验室观测结果来开发和评估模型。将 PTW 排放量与特定情景相结合，以排放量占吞吐量的百分比来看待。车辆排气管和曲轴箱排放是甲烷的最高排放源。作者正在将本研究中的数据应用于开发模型，以预测未来 HD 运输部门的甲烷排放情况。
